lualoader: Refactor config line expressions

A couple of issues addressed:

1.) Modules with - in the name were not recognized as modules
2.) The module regex was repeated for each place a module name may appear
3.) The 'strip leading space' bits were repeated for each expression
4.) The trailing 'comment validation' stuff was repeated every expression

#4 still has some more work to be done. exec lines, for instance, don't
capture a 'value' -- there's only one capture pattern. This throws off the
'c' value that we match, so the trailing bits aren't *actually* being
validated. This isn't a new issue, though, so a future comit will address
this.